Hydroprocessing method with high liquid mass flux

ABSTRACT

In a method of hydroprocessing, hydrogen gas for the hydroprocessing reaction is combined with a liquid feed composition comprising a feedstock to be treated and a diluent to form a feed stream, at least a portion of the hydrogen gas being dissolved in the liquid feed composition of the feed stream, with non-dissolved hydrogen gas being present in the feed stream in an amount of from 1 to 70 SCF/bbl of the liquid feed composition. The feed stream is contacted with a hydroprocessing catalyst, within a reactor while maintaining a liquid mass flux within the reactor of at least 5000 lb/hr·ft2 to form a hydroprocessed product.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/200,816, filed Aug. 4, 2015, which is incorporated herein byreference in its entirety for all purposes.

FIELD OF THE INVENTION

The invention relates to a hydroprocessing process wherein a liquidfeedstock is catalytically reacted with hydrogen inside a reactor.

BACKGROUND

In hydroprocessing, which may include hydrotreating, hydrofinishing,hydrorefining, and hydrocracking, a catalyst is used for reactinghydrogen with hydrocarbons, such as a petroleum fraction, distillates,resids, or other hydrocarbon compounds, for the purpose of saturatingolefins or removing heteroatoms, such sulfur, nitrogen, oxygen, metals,or other contaminants, or for molecular weight reduction (cracking).Catalysts having special surface properties are required in order toprovide the necessary activity to accomplish the desired reaction(s).

In conventional hydroprocessing it is necessary to transfer hydrogenfrom a vapor phase into the liquid phase where it is available to reactwith a hydrocarbon molecule at the surface of the catalyst. This isaccomplished by circulating very large volumes of hydrogen gas and theliquid hydrocarbon feed through a catalyst bed. The liquid feed and thehydrogen flow through the bed and the hydrogen is absorbed into a thinfilm of liquid hydrocarbon that is distributed over the catalyst.Because the amount of hydrogen gas required for the hydroprocessingreaction can be quite large, e.g., 1000 to 5000 SCF/bbl (0.178 to 0.890m³/L) of liquid, the reactors are very large and are operated at severeconditions, from a few hundred psi to as much as 5000 psi (34.5 MPa),and temperatures from around 400° F.-900° F. (204° C.-482° C.).Furthermore, because conventional processes move very large quantitiesof hydrogen gas through the reactor, they also require the use of verylarge external high-pressure separators to recover gas from the productstream. These high-pressure separators may be as large as thehydroprocessing reactors and are a significant capital equipment cost.

Hydroprocessing rates are typically measured in terms of mass flux,which can be defined as the mass flow rate per unit area. In a reactorthe mass flux is the mass flow rate through a reactor divided by thecross-sectional area of the reactor. Typical mass flux inhydroprocessing reactors fall in the range of from 1,000 lb/hr·ft² (4880kg/hr·m²) to less than 5,000 lb/hr·ft² (24,400 kg/hr·m²). Although it ispreferable to move liquid feedstocks through the reactor at the greatestrate and volume as possible (i.e., a higher mass flux), a variety oflimitations, including excessive pressure drop, hydrogen mass transferconcerns, liquid holdup, and wetting inefficiencies, have necessitatedthat mass flux rates remain within the range of from 1,000 lb/hr·ft²(4880 kg/hr·m²) to less than 5,000 lb/hr·ft² (24,400 kg/hr·m²) foroptimum process efficiency.

A method for hydroprocessing is disclosed in U.S. Pat. No. 4,937,051,entitled Catalytic Reactor with Liquid Recycle, issued to Graven et al.on Jun. 26, 1990. Graven et al. discloses a continuous catalytic reactorcolumn for contacting oil and a treating gas in a multiphase fixed bedcatalytic reactor having at least two operatively connected catalystbeds . . . and including means for maintaining total liquid flux in atleast one catalyst bed at a rate of about 2000 lb/hr·ft² (9760kg/hr·m²). Graven et al. also states that, “[i]a typical multi-phasereactor system, the average gas-liquid volume ratio in the catalyst zoneis about 1:4 to 20:1 under process conditions. Preferably the liquid issupplied to the catalyst bed at a rate to occupy about 10 to 50% of thevoid volume.”

A typical range for mass flux in a hydroprocessing reactor is disclosedin U.S. Pat. No. 7,655,135, entitled Process for Removing SolidParticles from a Hydroprocessing Feed, issued to Havlik et al. on Feb.2, 2010. Havlik, et al., discloses a process for removing inorganicsolid contaminants 10 microns and smaller from a hydroprocessing feedstream wherein lower mass fluxes are expected to allow a higherutilization factor due to lower velocities which promotes solids laydownin a guard bed that has the purpose of trapping solids before a feed isintroduced into a typical hydroprocessing reactor. Havlik et al.suggests a preferred mass flux of 500 lb/hr·ft² (2440 kg/hr·m²) and amore preferred mass flux of 1,000 lb/hr·ft² (4880 kg/hr·m²) for theguard bed in the disclosed invention. Havlik et al. goes on to providean example of a 20,000 bbl/day (3179 m³/day) gas-to-liquids plantwherein the guard bed operates at a mass flux of half of the mass fluxof the subsequent hydrocracker, which is disclosed as being as 1500lb/hr·ft² (7320 kg/hr·m²).

U.S. Pat. No. 6,569,313, entitled Integrated Lubricant UpgradingProcess, issued to Carroll et al. provides further support of thetypically accepted mass flux in catalytic hydroprocessing. It isdescribed therein that in the preferred embodiment the catalyticdewaxing segment of the process advantageously, the liquid flux rate fortotal feed rate (including optional liquid recycle) is maintained in therange of 500-3500 lb/hr·ft² (2440-17,100 kg/hr·m²), preferably 1000-3000lb/hr·ft² (4880-14,600 kg/hr·m²).

In U.S. Pat. App. Pub. No. 2012/0074038, entitled Liquid PhaseHydroprocessing with Low Pressure Drop, of Petri et al., a process isdisclosed wherein the mass flux in a hydroprocessing reactor may be inexcess of 6000 lb/hr·ft² (29,300 kg/hr·m²). This process is limited inthat the average size of the catalyst particles utilized must be in therange of 100 nm-1.27 mm. As stated therein, larger catalyst sizesrequire that the mass flux of the reactor be reduced.

SUMMARY

In a method of hydroprocessing hydrogen gas for the hydroprocessingreaction is combined with a liquid feed composition comprising afeedstock to be treated and a diluent to form a feed stream. At least aportion of the hydrogen gas is dissolved in the liquid feed compositionof the feed stream, with non-dissolved hydrogen gas being present in thefeed stream in an amount of from 1 to 70 SCF/bbl (0.000178 to 0.0125m³/L) of the liquid feed composition. The feed stream is contacted witha hydroprocessing catalyst within a reactor while maintaining a liquidmass flux within the reactor of at least 5000 lb/hr·ft² (24,400kg/hr·m²) to form a hydroprocessed product.

In particular embodiments the feedstock may be at least one of apetroleum feedstock, a non-petroleum feedstock, a bio oil, a pyrolysisoil, a high-contaminant feedstock, and a high-olefinic feedstock.

The feed stream may be contacted with a hydroprocessing catalystcontained in at least two catalyst beds within the reactor.

In some embodiments, the non-dissolved hydrogen gas in the feed streammay be present in an amount of from 1 to 50 SCF/bbl (0.000178 to 0.0089m³/L) of the liquid feed composition.

The liquid mass flux within the reactor may be maintained at from 5000to 100,000 lb/hr·ft² (24,400 to 488,000 kg/hr·m²) in particularembodiments. In others, the liquid mass flux within the reactor may bemaintained at from 10,000 lb/hr·ft² (48,800 kg/hr·m²) or more. In stillothers, the liquid mass flux within the reactor may be maintained atfrom 30,000 lb/hr·ft² (146,000 kg/hr·m²) or more.

In particular embodiments, at least a portion of the hyroprocessedproduct is used to form the diluent.

In further embodiments, gas is separated from liquid hydroprocessedproduct in a separator located within the reactor.

Liquid levels may be maintained within the reactor by controlling theamount of hydrogen gas added to the feedstream. Further, the volume ofgas within the reactor is maintained in a near stagnant condition.

In another method of hydroprocessing, hydrogen gas for thehydroprocessing reaction is combined with a liquid feed compositioncomprising a feedstock to be treated and a diluent to form a feedstream. At least a portion of the hydrogen gas is dissolved in theliquid feed composition of the feed stream, with non-dissolved hydrogengas being present in the feed stream in an amount of from 1 to 50SCF/bbl (0.000178 to 0.0089 m³/L) of the liquid feed composition. Thefeed stream is contacted with a hydroprocessing catalyst contained in atleast two catalyst beds contained within a reactor while maintaining aliquid mass flux within the reactor of from 10,000 to 100,000 lb/hr·ft²(48,800 to 488,000 kg/hr·m²) to form a hydroprocessed product.

The liquid mass flux within the reactor may be maintained at from 30,000lb/hr·ft² (146,000 kg/hr·m²) or more in some embodiments.

In particular embodiments, at least a portion of the hyroprocessedproduct is used to form the diluent.

In further embodiments, gas is separated from liquid hydroprocessedproduct in a separator located within the reactor.

Liquid levels may be maintained within the reactor by controlling theamount of hydrogen gas added to the feedstream. Further, the volume ofgas within the reactor is maintained in a near stagnant condition, whichmay be accomplished by controlling the separated gas removed from thereactor.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the disclosure, reference is nowmade to the following descriptions taken in conjunction with theaccompanying figures, in which:

FIG. 1 is a schematic of a hydroprocessing reactor showing the processflow in accordance with particular embodiments of the invention.

DETAILED DESCRIPTION

The present invention is directed to a hydroprocessing method wherein aliquid diluent is mixed with a liquid hydrocarbon feedstock to betreated and combined with an excess quantity of hydrogen to form adiluent/feedstock/dissolved hydrogen mixture. The mixture enters ahydroprocessing reactor, along with additional hydrogen gas. Liquid andgas flow cocurrently over a catalyst bed in a trickle-like fashion,where liquid flows over the catalyst through a volume of gas.

The process that has been developed wherein the liquid mass flux in ahydroprocessing reactor is significantly greater than the liquid massflux of conventional hydroprocessing methods. This is accomplished byreducing the hydrogen gas requirement inside the reactor.

As discussed previously, liquid mass flux is defined as the rate of massflow per unit area. It can be calculated by dividing the amount of massflowing through the reactor at a given time by the cross-sectional areaof the reactor. Liquid mass flux is typically expressed in units ofpounds per hour per square foot (lb/hr·ft²) in hydroprocessingapplications.

Typical liquid mass flux in conventional hydroprocessing reactors fallsin the range of 1,000 lb/hr·ft² (4880 kg/hr·m²) to less than 5,000lb/hr·ft² (24,400 kg/hr·m²). Although it is preferable to move liquidfeedstocks through the reactor at the greatest speed and volume aspossible (i.e. higher liquid mass flux), a variety of limitations,including excessive pressure drop, hydrogen mass transfer concerns,liquid holdup, and wetting inefficiencies, have necessitated that liquidmass flux rates remain within the range of 1,000 lb/hr·ft² (4880kg/hr·m²) to less than 5,000 lb/hr·ft² (24,400 kg/hr·m²) for optimumprocess efficiency.

In contrast, processes are disclosed herein wherein hydroprocessingreactors can efficiently operated with a liquid mass flux in the rangeof at or above 5,000 lb/hr·ft² (24,400 kg/hr·m²) with no constraints onfeedstock quality or catalyst size or material. In particularembodiments, the liquid mass flux may range from at or above 6000lb/hr·ft² (29,300 kg/hr·m²), 7000 lb/hr·ft² (34,200 kg/hr·m²), 8000lb/hr·ft² (39,100 kg/hr·m²), 9000 lb/hr·ft² (43,900 kg/hr·m²), 10,000lb/hr·ft² (48,800 kg/hr·m²), 15,000 lb/hr·ft² (73,200 kg/hr·m²), 20,000lb/hr·ft² (97,600 kg/hr·m²), 25,000 lb/hr·ft² (122,000 kg/hr·m²), 30,000lb/hr·ft² (146,000 kg/hr·m²) to 40,000 lb/hr·ft² (195,000 kg/hr·m²),50,000 lb/hr·ft² (244,000 kg/hr·m²), 60,000 lb/hr·ft² (293,000kg/hr·m²), 70,000 lb/hr·ft² (342,000 kg/hr·m²), 80,000 lb/hr·ft²(391,000 kg/hr·m²), 90,000 lb/hr·ft² (439,000 kg/hr·m²), 100,000lb/hr·ft² (488,000 kg/hr·m²) or more.

It should be noted in the description, if a numerical value or range ispresented, each numerical value should be read once as modified by theterm “about” (unless already expressly so modified), and then read againas not so modified unless otherwise indicated in context. Also, in thedescription, it should be understood that an amount range listed ordescribed as being useful, suitable, or the like, is intended that anyand every value within the range, including the end points, is to beconsidered as having been stated. For example, “a range of from 1 to 10”is to be read as indicating each and every possible number along thecontinuum between about 1 and about 10. Thus, even if specific pointswithin the range, or even no point within the range, are explicitlyidentified or refer to, it is to be understood that the inventorsappreciate and understands that any and all points within the range areto be considered to have been specified, and that inventors possessesthe entire range and all points within the range.

In addition to dramatically higher liquid mass flux in thehydroprocessing reactors, the need for the large high-pressuregas/liquid separators required by conventional hydroprocessing methodsis also eliminated. Because of the very small amount of hydrogen gasadded into the reactor, the quantities of gas present in the finalproduct are drastically lower. Therefore, the large high-pressureseparators can be replaced with very small hot high-pressure separators.These separators can be operated at or near reactor conditions (i.e.,temperature and pressure). This translates into a significant costsavings. These small hot high-pressure separators can be located outsideof the reactor, as are high-pressure separators in conventionalprocesses, or, because of their small size, the hot high-pressureseparators of the present invention may be placed or be located insidethe reactor itself. If these small, hot high-pressure separators arelocated inside the reactor, they can serve the added function ofcontrolling the quantity of hydrogen gas being added to the reactor, asis discussed more fully below.

The hydroprocessing process utilized may include, but is not necessarilylimited to, hydrotreating, hydrofinishing, hydrorefining, hydrocracking,hydroisomerization, Fischer-Tropsch, and/or hydrodemetalization process.Suitable catalysts and reaction conditions for such processes are used.Those catalysts used for reacting hydrogen with hydrocarbons, such as apetroleum fraction, distillates, resids, or other hydrocarbon compounds,for the purpose of saturating olefins or removing heteroatoms, suchsulfur, nitrogen, oxygen, metals, or other contaminants, or formolecular weight reduction (cracking) may be used. The amount ofcatalyst used may be that that provides sufficient conversion. In someembodiments, different catalysts may be used in the same catalyst bed ordifferent catalysts beds of the reactor. Reactor temperatures typicallyrange from 250° F. to 800° F. (120° C. to about 430° C.), moreparticularly from 500° F. to 800° F. (260° C. to 430° C., with from 500°F. to 650° F. (260° C. to 340° C.) being useful in many applications.Reactor pressures may range from 500 psi (3.5 MPa) or more, with from500 psi to 3000 psi (3.5 MPa to 21 MPa) being useful in manyapplications. In certain embodiments, the catalysts used may be thosehaving particles with a largest dimension that averages greater than1.27 mm

The hydroprocessing process may be used for treating hydrocarbonfeedstocks from petroleum products, as are treated in conventionalhydroprocessing. In certain applications, however, the hydrocarbon feedmay be a non-petroleum feedstock derived from non-petroleum materials.These may be materials derived from or based on vegetable, animal, andcellulosic materials, coal, and combinations of such materials. Thefeedstocks may also include pyrolysis oils derived from petroleum andnon-petroleum materials.

In some applications, the feedstock may include high-contaminant and/orhigh-olefinic feedstocks, which is often the case for non-petroleummaterials, although petroleum feedstocks may also be high-contaminantand/or high-olefinic feedstocks in certain instances. As used herein,high-contaminant feed stocks are those containing heteroatoms, such assulfur, nitrogen, oxygen, and metals, which may be at levels of from 10%or more by weight of the feed. High-olefinic feedstocks are those havingfrom 10% or more of olefinic molecules by weight of the feed. As usedherein, with respect to olefinic compounds weight percentages are basedon weight of the olefinic molecules. With respect to heteroatomcontaminants, weight percentages are based upon the weight of theheteroatoms. Such olefinic compounds and heteroatom contaminants may beat levels of from about 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50% ormore by weight or more of the feedstock. In particular, the olefiniccompounds and heteroatom contaminants may make up from about 10% toabout 50% by weight of the feedstock. In certain embodiments, the feedstock may have an oxygen content of from about 10%, 15%, 20%, 25%, 30%,35%, 40%, 45%, 50% by weight or more. When treating suchhigh-contaminant and/or high-olefinic feedstocks, modifications,undesirable byproducts and process considerations, such as increasedlevels of water must be taken into account. Techniques, such as thoseused in U.S. Pat. No. 9,096,804, which is hereby incorporated byreference herein for all purposes, may be used in the process describedherein to accommodate the hydroprocessing of high-contaminant andhigh-olefinic feedstocks.

In the hydroprocessing process, the hydrogen necessary for thehydroprocessing reaction is combined as hydrogen gas with a liquid feedcomposition comprising a hydrocarbon feedstock or fresh feed to betreated and a liquid diluent to form a feed stream. This is done withoutintroducing and circulating additional hydrogen gas in the reactor, aswith conventional hydroprocessing. The liquid diluents may include, butare not limited to light hydrocarbons, distillates, VGO, or previouslyhydroprocessed stocks. This may include a recycled portion of the liquidhydroprocessed product formed in the hydroprocessing reaction. Theliquid diluent is mixed with fresh hydrocarbon feedstock in a ratioranging from about 0.5:1 to about 10:1 to form a diluent/fresh feedmixture.

The diluent/fresh feed mixture is then combined with an excess quantityof hydrogen gas. The type and amount of diluent in the diluent/freshfeed mixture is selected so that a substantial portion of the hydrogengas combined with the liquid feed composition is dissolved in the liquidfeed composition to form a diluent/fresh feed/dissolved hydrogenmixture. The hydrogen gas is added to the liquid diluent/fresh feedmixture in an amount so that a portion of the hydrogen gas added remainsas a gas and is not dissolved within the liquid feed composition. Thisportion of non-dissolved hydrogen gas remains present in the feed streamin an amount of from 1 to 70 SCF/bbl (0.000178 to 0.0125 m³/L) of theliquid feed composition. In particular embodiments, the non-dissolvedhydrogen gas in the feed stream may be present in an amount of from 1 to50 SCF/bbl (0.000178 to 0.0089 m³/L) of the liquid feed composition.This may translate to a liquid volume of approximately 10 to 500 timesgreater than the volume of gas.

The hydrogen gas is combined with the liquid diluent/fresh feed mixtureand may be introduced into the hydroprocessing reactor without anyseparation step ahead of the reactor to remove excess hydrogen gas fromthe feed stream. In other embodiments, separation of hydrogen gas aheadof the reactor may occur to provide residual non-dissolved hydrogen gasprovided that it is within those limited amounts as discussed above. Thehydrogen gas added to the liquid diluent/fresh feed mixture to form thefeed stream introduced into the reactor is that necessary for thehydroprocessing reaction. No further hydrogen gas may be added to thereactor other than that combined with the liquid diluent/fresh feedmixture to form the feed stream introduced into the hydroprocessingreactor. Furthermore, the addition of hydrogen gas to the feed streamintroduced into the reactor may be used to control liquid levels withinthe reactor, as is discussed later on.

The gas within the volume of the reactor may be maintained in a nearstagnant condition. This may be achieved by controlling the removal ofgas from the reactor so that the hydrogen gas flow through the reactormay be at or less than 5 ACF/hr (actual cubic ft/hr) (0.142 m³/hr) perft³ (0.03 m³) of reactor volume. In particular embodiments the hydrogengas flow through the reactor may be from 0.2 ACF/hr (0.0056 m³/hr), 0.3ACF/hr (0.0085 m³/hr), 0.4 ACF/hr (0.0113 m³/hr), or 0.5 ACF/hr (0.0142m³/hr) per ft³ (0.03 m³) of reactor volume to 3 ACF/hr (0.085 m³/hr), 4ACF/hr (0.113 m³/hr), or 5 ACF/hr (0.142 m³/hr) per ft³ (0.03 m³) ofreactor volume.

Referring to FIG. 1, a schematic of a hydroprocessing system 10 forcarrying out the methods described herein is shown. The system 10includes a hydroprocessing reactor 12 formed from a reactor vessel 14that houses the various internal components of the reactor 12. Thereactor 12 is provided with an inlet 16 at the upper end of the reactor12 for introducing a feed stream into the interior of the reactor vessel14. The inlet 16 is fluidly coupled to a feed line 18 for delivering afeed stream to the inlet 16.

The feed stream is formed by combining a fresh liquid hydrocarbon feedor feedstock to be treated from fresh feed line 20 that is combined withdiluent or recycled liquid hydroprocessed product from lines 22, 24,respectively, to form a liquid feed composition in line 26. Hydrogen gasfrom line 28 fluidly coupled to a hydrogen gas source is combined withthe liquid feed composition from line 26 to form the feed stream of line18. The amount of hydrogen gas added through line 28 is controlled bycontrol valve 30.

The intermixed liquid composition and excess hydrogen gas feed streamfrom line 18 is fed through upper inlet 16 into the top of ahydroprocessing reactor 12 to a distributor 32. The feed streamintroduced to the reactor 12 is introduced at a rate to provide the highliquid mass flux rate discussed previously. The reactor vessel 14 housesa first catalyst bed 34 in an upper portion of the reactor containing ahydroprocessing catalyst supported by screens or other supportstructures. The introduced intermixed liquid composition and excesshydrogen gas may flow onto a vapor/liquid distributor tray 32 where thegas and liquid flow cocurrently from the distributor 32 over the firstcatalyst bed 34 in a trickle-like fashion, wherein the liquid flows overthe catalyst through a nearly stagnant volume of gas within the reactorvessel interior. Reacted liquid exits the first catalyst bed 34 andfalls through the nearly stagnant gas onto a chimney tray 36 whereliquid and gas are separated and where the liquid level 38 may bemaintained by the addition of hydrogen gas introduced through line 28. Aliquid level controller 40 coupled to control valve 30 may be used tocontrol the hydrogen gas introduced through line 28 at the diluent/freshfeed/hydrogen mixer.

Referring to FIG. 1, liquid from chimney tray 36 is discharged throughoutlet collector 42 to a distributor 44 of a second lower reaction zone.The effluent from the chimney tray 36 is passed from the distributortray 44 to a second catalyst bed 46, which may contain the same or adifferent hydroprocessing catalyst from that of the upper catalyst bed34. The liquid and hydrogen gas flow cocurrently over through the secondcatalyst bed 46 in a trickle-like fashion through a nearly stagnantvolume of gas. This process may be repeated with additional catalystbeds as needed or desired.

At the final stage of hydroprocessing, the reacted liquid and gas flowfrom the catalyst bed 46 to a final distributor tray 48. In thisparticular embodiment, the liquid and gas are then separated in a hothigh-pressure separator 50 housed at the base or lower end of thereactor vessel 14, wherein gas and liquids are separated at or nearreactor conditions (i.e., temperature and pressure). The gas flow off ofthe hot high-pressure separator is discharged from the reactor throughline 52. A control valve 54 may be used to control the gas flow so thatthe volume of gas within the reactor 12 is nearly stagnant. In otherembodiments, the liquid and gas may be removed from the reactor andseparated at or near reactor conditions in an external gas/liquidseparator (not shown) that is external to the reactor vessel 14.

Separated liquid hydroprocessed product is removed from the bottomportion of the reactor vessel 14 through line 56 to pump 58. All or aportion of the liquid hydroprocessed product may be removed through line60 for collection and storage or further processing. In someembodiments, a portion of the liquid hydroprocessed product may bepassed to from pump 60 to recycle line 24, where it is mixed with thefresh liquid feed to be treated from line 20, as discussed earlier.

In an alternative embodiment of the process described above, at thechimney tray 36 in the upper zone of the reactor 12 additional excesshydrogen gas from line 62 is introduced into the reactor 12 withinchimney tray 36. The amount of hydrogen gas added at this intermediatestage may be controlled so that the quantity of excess hydrogen gaspresent in the liquid from chimney tray 36 and discharged through outletcollector 42 to the second vapor/liquid distributor tray 44 is heldwithin the range described previously (i.e., 1 to 70 SCF/bbl (0.000178to 0.0125 m³/L) of the liquid feed composition, etc.). The liquid andgas flow cocurrently over the second catalyst bed 46 in a trickle-likefashion through a nearly stagnant volume of gas. This process may berepeated with additional catalyst beds as needed or desired.

At the final stage of hydroprocessing, the reacted liquid and gas flowthrough the final catalyst bed 46 to the final chimney tray 48, where itis collected. In certain embodiments, the liquid level 64 in the chimneytray 48 at the bottom of the reactor may be further maintained by theaddition of hydrogen gas introduced through line 62. A liquid levelcontroller 66 coupled to control valve 68 on line 62 may be used tocontrol the hydrogen gas introduced through line 62.

The liquid and gas are then separated in separator 50 at or near reactorconditions, with gas being removed through line 52 and liquidhydroprocessed product being discharged through line 56 through pump 58at a constant rate. In other embodiments, the liquid and gas may beremoved from the reactor 12 and separated external to the reactor but ator near reactor conditions in an externally located gas/liquid separator(not shown).

While the invention has been shown in only some of its forms, it shouldbe apparent to those skilled in the art that it is not so limited, butis susceptible to various changes and modifications without departingfrom the scope of the invention. Accordingly, it is appropriate that theappended claims be construed broadly and in a manner consistent with thescope of the invention.

We claim:
 1. A method of hydroprocessing comprising: combining hydrogengas for the hydroprocessing reaction with a liquid feed compositioncomprising a feedstock to be treated and a diluent to form a feedstream, a portion of the hydrogen gas being dissolved in the liquid feedcomposition of the feed stream, with non-dissolved hydrogen gas beingpresent in the feed stream in an amount of from 1 SCF to 70 SCF per bblof the liquid feed composition; and contacting the feed stream with ahydroprocessing catalyst of a catalyst bed while the liquid feedcomposition flows through a volume of nearly stagnant gas within areactor and while maintaining a liquid mass flux within the reactor ofat least 5000 lb/hr·ft² or more to form a hydroprocessed product; andfurther comprising separating gas from liquid hydroprocessed product ina separator located within the reactor downstream from the catalyst bed.2. The method of claim 1, wherein: the feedstock comprises at least oneof a petroleum feedstock, a non-petroleum feedstock, a bio oil, apyrolysis oil, a high-contaminant feedstock, and a high-olefinicfeedstock.
 3. The method of claim 1, wherein: the feed stream iscontacted with a hydroprocessing catalyst contained in at least twocatalyst beds within the reactor.
 4. The method of claim 1, wherein: thenon-dissolved hydrogen gas in the feed stream is present in an amount offrom 1 SCF to 50 SCF per bbl of the liquid feed composition.
 5. Themethod of claim 1, wherein: the liquid mass flux within the reactor ismaintained at from 5000 lb/hr·ft² to 100,000 lb/hr·ft².
 6. The method ofclaim 1, wherein: the liquid mass flux within the reactor is maintainedat from 6000 lb/hr·ft² to 100,000 lb/hr·ft².
 7. The method of claim 1,wherein: the liquid mass flux within the reactor is maintained at from10,000 lb/hr·ft² or more.
 8. The method of claim 1, wherein: the liquidmass flux within the reactor is maintained at from 30,000 lb/hr·ft² ormore.
 9. The method of claim 1, wherein: at least a portion of thehyroprocessed product is used to form the diluent.
 10. The method ofclaim 1, wherein: the liquid mass flux within the reactor is maintainedat greater than 10,000 lb/hr·ft².
 11. The method of claim 1, wherein:the separated gas is removed from the reactor at a rate so that thevolume of gas within the reactor is maintained in a near stagnantcondition.
 12. The method of claim 1, further comprising: maintaining aliquid level within the reactor by controlling the amount of hydrogengas added to the feedstream.
 13. The method of claim 1, wherein: thevolume of nearly stagnant gas has a flow rate of from 5 ACF/hr or lessper ft³ of reactor volume.
 14. A method of hydroprocessing comprising:combining hydrogen gas for the hydroprocessing reaction with a liquidfeed composition comprising a feedstock to be treated and a diluent toform a feed stream, a portion of the hydrogen gas being dissolved in theliquid feed composition of the feed stream, with non-dissolved hydrogengas being present in the feed stream in an amount of from 1 SCF to 50SCF per bbl of the liquid feed composition; and contacting the feedstream with a hydroprocessing catalyst contained in at least twocatalyst beds contained within a reactor while the liquid feedcomposition flows through a volume of nearly stagnant gas and whilemaintaining a liquid mass flux within the reactor of from 10,000lb/hr·ft² to 100,000 lb/hr·ft² to form a hydroprocessed product; andfurther comprising separating gas from liquid hydroprocessed product ina separator located within the reactor downstream from at least one ofthe catalyst beds.
 15. The method of claim 14, wherein: the feedstockcomprises at least one of a petroleum feedstock, a non-petroleumfeedstock, a bio oil, a pyrolysis oil, a high-contaminant feedstock, anda high-olefinic feedstock.
 16. The method of claim 14, wherein: theliquid mass flux within the reactor is maintained from 30,000 lb/hr·ft²to 100,000 lb/hr·ft².
 17. The method of claim 14, wherein: at least aportion of the hyroprocessed product is used to form the diluent. 18.The method of claim 14, wherein: the separated gas is removed from thereactor at a rate so that the volume of gas within the reactor ismaintained in a near stagnant condition.
 19. The method of claim 14,wherein: the volume of nearly stagnant gas has a flow rate of from 5ACF/hr or less per ft³ of reactor volume.
 20. The method of claim 14,further comprising: maintaining a liquid level within the reactor bycontrolling the amount of hydrogen gas added to the feedstream.